Where is the coolant temperature sensor on a 1999 Nissan Altima?
The coolant temperature sensor on a 1999 Nissan Altima is located on the passenger side of the engine block. It is screwed into the engine block under the intake manifold. The wire connector is attached to the top of the sensor. To remove the coolant temperature sensor, disconnect the wire connector and then use a 19 mm wrench to loosen the sensor from the engine block. Be careful not to drop the sensor into the engine block.